Dark Matter

Astronomers using NASA’s Hubble Space Telescope received a boost from a cosmic magnifying glass to construct one of the sharpest maps of dark matter in the universe. They used Hubble’s Advanced Camera for Surveys to chart the invisible matter in the massive galaxy cluster Abell 1689, located 2.2 billion light-years away. The cluster contains about 1,000 galaxies and trillions of stars. Dark matter is an invisible form of matter that accounts for most of the universe’s mass. Hubble cannot see the dark matter directly. Astronomers inferred its location by analyzing the effect of gravitational lensing, where light from galaxies behind Abell 1689 is distorted by intervening matter within the cluster.

Researchers used the observed positions of 135 lensed images of 42 background galaxies to calculate the location and amount of dark matter in the cluster. They superimposed a map of these inferred dark matter concentrations, tinted blue, on a Hubble image of the cluster. The new dark matter observations may yield new insights into the role of dark energy in the universe’s early formative years.

from:
http://eaae-astronomy.org/blog/?cat=49

The Best Meteor Shower Of The Year

There are several major meteor showers to enjoy every year at various times, with some more active than others. The 2010 Leonid meteor shower peaks the evening of Wednesday, Nov. 17.

If you’re viewing in dark conditions, the best viewing time will be after midnight, in the hours just before dawn. But don’t expect too much. While the annual shower has been spectacular in the past, this year’s 85% full moon will obstruct viewing for most backyard astronomers. At most, expect to see approximately 15 meteors per hour.

Whether you’re watching from a downtown area or the dark countryside, here are some tips to help you enjoy these celestial shows of shooting stars. Those streaks of light are really caused by tiny specks of comet-stuff hitting Earth’s atmosphere at very high speed and disintegrating in flashes of light.

Sky and telescope

Tuesday, November 16

This evening the Moon is to Jupiter's upper left.

The Leonid meteor shower should be at its best in the early hours of Wednesday and/or Thursday — after the Moon sets around 3 a.m. Wednesday morning, and 4 a.m. Thursday morning. But the Leonids have been far from spectacular in these off-years. You might see 20 Leonids per hour, and 4 Taurids, from a dark, rural site.

In the Wednesday dawn, Venus is the closest it will get to fainter Spica: 3 3/4° below it.

Повече информация за периода 12-20 ноември на:

http://www.skyandtelescope.com/observing/ataglance

The Scale of the Universe

http://htwins.net/scale/

Carl Sagan Day - November 9

Today is Carl Sagan Day — a chance to remember the legacy of one of the greatest science promoters ever. Carl Edward Sagan (November 9, 1934 – December 20, 1996) was an American astronomer, astrophysicist, author, cosmologist, and highly successful popularizer of astronomy, astrophysics and other natural sciences.

Comet 103P/Hartley 2

На 4.11.2010г. сутринта космоческият кораб на НАСА Deep Impact направи снимка на ядрото на кометата 103P/Hartley 2, Обърнете внимание на много струи газ, произтичащи от краищата на продълговатото тяло, което учените оприличават на фъстък.


по материали на списание "Sky and Telescope"
http://www.skyandtelescope.com/news/home/106720468.html

demonstrator